The PowerPC is mainly used in the Xbox360 but not the PS3.
The CPU used in the PS3 is a PowerPC based processor. In fact the Xenon processor used in the Xbox 360 made use of some of the Cell processor development (wonder what Sony thought of this...).
http://en.wikipedia.org/wiki/Cell_(microprocessor)
Cell (microprocessor) - Wikipedia, the free encyclopedia
Moore's law is almost coming to an end, its getting very difficult to shrink much further and its not a given that the issues can be overcome.
Moore's Law talks about the number of transistors in a processor not speed or anything else, and still appears to be valid. The difference is that now transistor counts are increasing through adding cores, GPUs and pulling in things like the memory controller.